Preparation Of Two-dimensional Layered Materials (LDHs, MXenes) Composites And Their Application In Electromagnetic Rheology

Two-dimensional?2D?layered materials have received considerable attention due to their excellent physical and chemical properties,and have become a research hotspot at present.Meanwhile,electro/magnetic-rheological?ER/MR?intelligent materials also have gained more and more attention.However,2D materials cannot be used as ER/MR materials directly based on their high conductivity and low paramagnetism.In this article,the recent advances in the study of layered 2D materials?LDHs and MXenes?and ER/MR materials were summarized.Layered 2D materials and their composites were synthesized through simple methods?hydrothermal methods,electrostatic adsorption,surface oxidation,etc.?and successfully applied to ER/MR,and their ER/MR properties and mechanisms were studied.Firstly,we prepared Ni-Al LDH by hydrothermal method.The Fe₃O₄/Ni-Al LDH nanocomposites were then synthesized by electrostatic adsorption.Fe₃O₄ nanoparticles have paramagnetic behavior and high saturation magnetization,Ni-Al LDH has abundant polarizing groups.The composites avoid the re-stacking of Ni-Al LDH and the aggregation of Fe₃O₄ NPs,and the sedimentation stability of their ER/MR liquids were improved.Furthermore,the composites are easy to prepare,low cost and environmentally friendly,so that the dual electro/magneto-stimuli-responsive Fe₃O₄/Ni-Al LDH-based smart fluid can be mass-produced and has great potential for industrial application.Secondly,the Ti₃C₂T_x MXene was prepared by HF etching,and then oxidized via hydrothermal method and CO₂ calcination derivatizing into a layered C/TiO₂ composite.It was successfully used as an ER material.The composite prepared by hydrothermal method showed an excellent ER effect.As for the composite prepared by CO₂ calcination,the size and number of TiO₂ particles increased with increasing calcination temperature,leading to an interesting electroresponsive behavior with great research value.This work broadens the application of MXenes and provides a possible pathway to predict and optimize the ER application for other 2D materials.